Plastic bags

Americans throw out 100,000,000,000 plastic shopping bags each year. This is the figure given in Katharine Mieszkowski’s article about plastic bags in Salon.com, which I first heard about when Sierra Club Radio Interviewed her.

I won’t repeat what’s in the article: that’s what links are for. Suffice it to say that plastic bags wreak havoc on the environment. But let’s explore the numbers.

As I write this, the Census bureau estimates the US population at 303,384,903: that means that, on average, each American throws away about 330 plastic bags each year, or just one bag per day most days of the year. Five bags of groceries plus two other purchases a week would do it; this tells us there’s no reason to doubt the 100 billion figure. In fact, thinking about all the double-bagging that goes on at supermarkets, and not to mention all the other shopping that’s going on all the time, the figure seems a bit low. And unfortunately, there isn’t one evil industrial polluter to which we can assign the blame: what seems like a normal number of plastic bags times a whole lot of us means a whole lot of bags.

Producing the 100,000,000,000 plastic bags apparently takes 12 million barrels of oil. One barrel of oil is 42 gallons, so you can make about 200 bags from a gallon of oil, or about 2/3 fluid ounce of oil per bag.

According to the US Department of Energy, the US uses 20.7 million barrels of oil per day, or 7.6 billion barrels of oil per year. Of this, roughly 3/4 goes to transportation fuels. So if we took all the oil that presently goes into plastic-bag production, and used it instead for moving around, it would last about 19 hours.

Which means: plastic bags are awful for wildlife, and very ugly when they’re littered around, but they’re not really a significant part of our dependence on foreign oil. If someone comes up with a scheme to recycle plastic bags into an alternative fuel for cars, then perhaps it will be clever, but it won’t really be anything like a solution.